Final answer:
In aviation, a low crew O2 pressure is indicated by a warning light or alarm on the oxygen panel. The pressure is sometimes displayed as PSI or mm Hg, and attention to it is crucial due to the potentially life-threatening effects of hypoxemia or hypoxia.
Step-by-step explanation:
An indication on the oxygen panel that the crew O2 pressure is low is typically denoted by a warning light or alarm within the aircraft's cockpit.
The specific design of the oxygen system will vary by aircraft, but nearly all systems include some form of visual or auditory alert when oxygen levels fall below a preset threshold. It is common to have a gauge that displays the pressure in terms of PSI (pounds per square inch) or in millimeters of mercury (mm Hg).
The partial pressure of oxygen is crucial since low levels can lead to states of hypoxemia or hypoxia, which can impair judgment, coordination, and can be life-threatening.
Oxygen deprivation symptoms such as fatigue, headaches, and confusion that are collectively referred to as hypoxia. A pulse oximeter is also often used in medical settings to measure the percent saturation of oxygen in blood, which is expected to be between 95-100 percent in healthy individuals. Any decrease from this range can be a concern that warrants immediate attention.